The present invention relates to a draft gear of the type of U.S. Pat. No. 3,178,037 wherein the draft gear comprises a piston in a cylinder with the cylinder having a fill of a flowable, normally solid material which material can pass from one side of the piston to the other through an orifice as draft and buff forces are applied to the draft gear. After the draft gear is completely manufactured, it is inserted into a pocket in the railway car. The draft gear and pocket are appropriately sized so that the draft gear is snug in the pocket under normal operating conditions of the railway car. To facilitate inserting the manufactured draft gear into the pocket, it is conventional to preshorten the draft gear, that is to retract the piston and piston rod, thus reducing the overall length of the draft gear and providing adequate clearance to permit the draft gear to be easily inserted into the pocket. A conventional practice for preshortening a draft gear of this kind is to provide a pair of diametrically opposed ears at the closed end of the draft gear housing. Each ear has an opening for accommodating a bolt parallel to the piston rod axis. The other end of each bolt passes through an opening in a heavy steel plate overlying the distal end of the piston rod. By tightening the nuts on the bolt the plate is drawn towards the closed end of the cylinder forcing the piston rod to a retracted position.
The present invention provides an easier and less expensive method and apparatus for preshortening the draft gear prior to its insertion into the railway car. In accordance with the present invention, during the manufacturing operation the piston is located in the preshortened position, part of the fill is inserted into the cylinder about the piston rod and the remainder of the fill is inserted into the cylinder between the piston and the closed end of the cylinder. The part of the fill about the piston rod holds the piston in the preshortened position. After the draft gear has been put into the railway car and the railway car is put in use, that part of the fill about the piston rod breaks down and allows the piston to move to the datum, or normal operating position.